i have finished dmc on devil hunter and nephilim or do i have to beat it on son of sparda difficulty?? i looked up how to unlock it and it says beat the game on a difficulty which i did so what gives? i might just download it again to see it that works

i have finished dmc on devil hunter and nephilim or do i have to beat it on son of sparda difficulty?? i looked up how to unlock it and it says beat the game on a difficulty which i did so what gives? i might just download it again to see it that works